[blueberry58]

I'm trying to prepare magnesium gluconate. I did not find gluconic acid, only sodium or calcium gluconate.

I think the next reaction would work fine:

CaC12H22O14 + Mg (OH) 2 = Ca (OH) 2 + MgC12H22O14

My problem is how to separate  gluconate salt from calcium hydroxide. I expected that hydroxide to be less soluble. Or is preferable other salt?

Have someone experience in this subject?

[billnotgatez]

I rewrote your formula to take advantage of the editing features on the posting page.
CaC₁₂H₂₂O₁₄ + Mg(OH) ₂  Ca(OH)₂ + MgC₁₂H₂₂O₁₄
C₁₂H₂₂CaO₁₄ + Mg(OH)₂  C₁₂H₂₂MgO₁₄ + Ca(OH)₂
Calcium gluconate + Magnesium hydroxide   Magnesium gluconate +  Calcium hydroxide

I'm trying to prepare magnesium gluconate. I did not find gluconic acid, only sodium or calcium gluconate.

I think the next reaction would work fine:

CaC12H22O14 + Mg (OH) 2 = Ca (OH) 2 + MgC12H22O14

My problem is how to separate  gluconate salt from calcium hydroxide. I expected that hydroxide to be less soluble. Or is preferable other salt?

Have someone experience in this subject?

[blueberry58]

Thank you Borek.

[Borek]

What do you know about solubilities of all substances involved?

[blueberry58]

Solubilities

Calcium Hydroxide   0.185 g/100 cm³
Magnesium gluconate  10 g / 100 cm³ 25°C

[Borek]

That's not enough. For the salt metathesis you need to compare solubilities of both products and reactants to be able to decide which way the reaction goes.

[blueberry58]

I already remembered this. The aim is to see what the salt tendency to crystallize sooner.

In past days I worked with no success separating magnesium thiosulfate and sodium chloride in solution. Salting out temp didnt work. Suppossedly MgThiosulfate should precipitate below 9 °C.

But I could find not data for a curve on sites that I know. CRC handbook doesnt include this data. I cant access Merck Index.  I would think cooling the products would precipite calcium chloride for its low solubility.

[blueberry58]

A patent on this subject (ion exchange resin)

http://www.google.tl/patents/US3670000

it show it is feasible but don't state some details of the process.

In this case as I understand resin must receive the ion to be exchanged and sodium on it must be removed.

[arbyflask]

Mix a solution of calcium gluconate with an equimolar solution of magnesium sulfate (AKA Epsom salt) - calcium sulfate should precipitate out, leaving magnesium gluconate in solution.

[Ahmed 97]

try to pass co2 in the solution to forms caco3